A hollow fiber mode field diameter measurement unit and system

Abstract

This invention discloses a hollow fiber mode field diameter measurement unit and system. The hollow fiber mode field diameter measurement unit includes a displacement stage, a hollow rotation mechanism, a first swing arm, a rotary motor, a second swing arm, and a detection mechanism. The hollow rotation mechanism is fixed on the displacement stage, which is used to change the spatial position of the hollow rotation mechanism. The hollow rotation mechanism is a hollow ring structure with a ring rotating part on its outer side. One end of the first swing arm is connected to the ring rotating part, and the other end of the first swing arm is connected to the rotary motor. The rotating end of the rotary motor is connected to the second swing arm, and the detection mechanism is connected to the end of the second swing arm. During measurement, the end of the hollow fiber being measured is positioned at the center of the hollow rotation mechanism. The hollow rotation mechanism controls the first swing arm to move in a circular motion around the end of the hollow fiber, and the rotary motor controls the second swing arm to move in a circular motion around the rotating end. The detection mechanism forms a composite scanning trajectory under the combined drive of the hollow rotation mechanism and the rotary motor.

Description

Technical Field

[0001] This invention relates to the field of hollow fiber testing technology, specifically to a hollow fiber mode field diameter measurement unit and system. Background Technology

[0002] The mode field diameter of hollow optical fibers is an important performance indicator, making its measurement crucial. The core of a hollow optical fiber is made of air, vacuum, or an inert gas, and the mode distribution is polygonal. Therefore, the mode field diameter needs to be measured in multiple dimensions, but currently available fiber mode field diameter testing systems lack multi-dimensional testing capabilities. Summary of the Invention

[0003] The purpose of this invention is to provide a hollow fiber mode field diameter measurement unit and system to achieve multi-dimensional measurement of the hollow fiber mode field diameter.

[0004] To solve the above-mentioned technical problems, the present invention provides a hollow fiber mode field diameter measurement unit, including a displacement stage, a hollow rotation mechanism, a first swing arm, a rotary motor, a second swing arm, and a detection mechanism;

[0005] The hollow rotating mechanism is fixed on the displacement stage, which is used to change the spatial position of the hollow rotating mechanism. The hollow rotating mechanism is a hollow ring structure with a ring rotating part on its outer side. One end of the first swing arm is connected to the ring rotating part, and the other end of the first swing arm is connected to the rotary motor. The rotating end of the rotary motor is connected to the second swing arm, and a detection mechanism is connected to the end of the second swing arm.

[0006] During measurement, the end of the hollow fiber being measured is positioned at the center of the hollow rotating mechanism. The hollow rotating mechanism controls the first swing arm to move in a circular motion around the end of the hollow fiber, while the rotating motor controls the second swing arm to move in a circular motion around the rotating end. The detection mechanism forms a composite scanning trajectory under the combined drive of the hollow rotating mechanism and the rotating motor.

[0007] According to the above scheme, the displacement stage is a first three-axis displacement stage, which is used to change the X, Y, and Z axis positions of the hollow rotating mechanism.

[0008] According to the above scheme, the detection mechanism includes a jumper bracket, an optical fiber jumper, and a photoelectric converter. The jumper bracket is connected to the end of the second swing arm. One end of the optical fiber jumper is fixed to the jumper bracket and serves as a scanning probe, while the other end is connected to the photoelectric converter. During measurement, the light emitted from the end of the hollow fiber being measured enters the optical fiber jumper and is then transmitted to the photoelectric converter and converted into an electrical signal. The electrical signals obtained by the scanning probe at different positions characterize the power distribution characteristics of the end of the hollow fiber being measured.

[0009] According to the above scheme, the measurement process includes: controlling the first swing arm to rotate at a preset step angle and then stopping through the hollow rotating mechanism, and then controlling the second swing arm to swing at a preset angle through the rotary motor, repeating the cycle until the first swing arm has traversed the preset angle range of the hollow rotating mechanism.

[0010] According to the above scheme, it includes an openable and closable first housing, which is used to shield ambient light when measuring the diameter of the mold field.

[0011] The present invention also provides a hollow fiber mode field diameter measurement system, including the hollow fiber mode field diameter measurement unit and the control unit described above; the control unit performs detection by controlling the detection mechanism to construct a power distribution image of the measured end of the hollow fiber.

[0012] According to the above scheme, it includes a light source coupling unit; the light source coupling unit includes a tunable wavelength light source, a second and third-axis displacement stage, and a power detection module; the second and third-axis displacement stage fixes the light source input end of the hollow fiber, and the light source input end of the hollow fiber is coupled to the tunable wavelength light source; the power detection module detects the power of the light emitted from the hollow fiber, the control unit calculates the coupling efficiency based on the power of the light emitted from the hollow fiber and the output power of the tunable wavelength light source, and adjusts the second and third-axis displacement stage based on the coupling efficiency feedback to change the position of the light source input end of the hollow fiber until the coupling efficiency is greater than a set threshold.

[0013] According to the above scheme, it includes an end face detection unit; the end face detection unit includes a background light compensation module and an end face detection module; the background light compensation module is used to provide back illumination for the tested end of the hollow fiber, and the end face detection module is used to acquire the end face image of the tested end of the hollow fiber.

[0014] The above scheme is applicable to hollow optical fibers with a cladding diameter of 100um to 1mm.

[0015] According to the above scheme, the light source coupling unit includes an openable and closable second housing, which is used to block ambient light when calculating the coupling efficiency.

[0016] Beneficial effects

[0017] This invention allows for flexible adjustment of the spatial position of the hollow rotating mechanism via a displacement stage, enabling precise adjustment of the relative position between the hollow rotating mechanism and the measured end of the hollow fiber. This ensures the measured end of the hollow fiber is accurately centered within the hollow rotating mechanism, providing a precise and stable reference for subsequent scanning measurements and effectively avoiding measurement deviations caused by positional offsets. The hollow rotating mechanism employs a hollow ring structure with an outer ring rotating part, driving the first swing arm to perform stable circular motion around the end of the hollow fiber. Simultaneously, a rotary motor drives the second swing arm to flexibly swing around its rotating end. The synergistic effect of these two components allows the detection mechanism to form a composite scanning trajectory, a trajectory design perfectly suited to the hollow fiber. The core requirement of polygonal mode spots and multi-dimensional measurement breaks through the limitations of traditional measurement systems that cannot achieve multi-dimensional testing. It can comprehensively cover all directions and dimensions of the measured end of hollow fiber, fully capture the mode field power distribution under different dimensions, and thus achieve multi-dimensional accurate measurement of the mode field diameter of hollow fiber. Through the design of combining the circular motion of the first swing arm with the swing of the second swing arm, there is no need to add additional complex transmission or adjustment components. While simplifying the structure of the measurement unit, it ensures the continuity and stability of the scanning action, improves the convenience and reliability of the measurement process, and provides strong support for accurately obtaining the key performance indicator of the mode field diameter of hollow fiber. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the hollow fiber mode field diameter measurement unit according to an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of a hollow fiber mode field diameter measurement system according to an embodiment of the present invention.

[0020] In the figure: 1. First three-axis displacement stage; 2. Hollow rotation mechanism; 3. First swing arm; 4. Rotary motor; 5. Second swing arm; 6. Jumper bracket; 7. Fiber optic jumper; 8. Photoelectric converter. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0022] See Figure 1 This embodiment discloses a hollow fiber mode field diameter measurement unit, including a displacement stage, a hollow rotation mechanism 2, a first swing arm 3, a rotary motor 4, a second swing arm 5, and a detection mechanism;

[0023] The hollow rotating mechanism 2 is fixed on the displacement stage, which is used to change the spatial position of the hollow rotating mechanism 2. The hollow rotating mechanism 2 is a hollow ring structure with a ring rotating part on its outer side. One end of the first swing arm 3 is connected to the ring rotating part, and the other end of the first swing arm 3 is connected to the rotary motor 4. The rotating end of the rotary motor 4 is connected to the second swing arm 5, and a detection mechanism is connected to the end of the second swing arm 5.

[0024] During measurement, the end of the hollow fiber being measured is positioned at the center of the hollow rotating mechanism 2. The hollow rotating mechanism 2 controls the first swing arm 3 to move in a circular motion around the end of the hollow fiber, and the rotating motor 4 controls the second swing arm 5 to move in a circular motion around the rotating end. The detection mechanism forms a composite scanning trajectory under the combined drive of the hollow rotating mechanism 2 and the rotating motor 4.

[0025] Furthermore, the displacement stage is a first three-axis displacement stage 1, which is used to change the X, Y, and Z axis positions of the hollow rotating mechanism 2.

[0026] Furthermore, the detection mechanism includes a jumper bracket 6, an optical fiber jumper 7, and a photoelectric converter 8. The jumper bracket 6 is connected to the end of the second swing arm 5. One end of the optical fiber jumper 7 is fixed to the jumper bracket 6 and serves as a scanning probe, while the other end is connected to the photoelectric converter 8. During measurement, the outgoing light from the measured end of the hollow fiber enters the optical fiber jumper 7 and is then transmitted to the photoelectric converter 8 and converted into an electrical signal. The electrical signals obtained by the scanning probe at different positions characterize the power distribution characteristics of the measured end of the hollow fiber.

[0027] Furthermore, the measurement process includes: controlling the first swing arm 3 to rotate at a preset step angle and then stopping through the hollow rotation mechanism 2, and then controlling the second swing arm 5 to swing at a preset angle through the rotary motor 4, repeating this process until the first swing arm 3 has traversed the preset angle range of the hollow rotation mechanism 2 (achieving a spherical scanning method, thereby achieving the measurement of the mode field diameter of any hollow fiber end face passing through the center of the fiber end face).

[0028] Specifically, the preset step angle of the hollow rotating mechanism 2 is 0.4° (which can also be set to 1° or other angles) of the scanning step length of the spherical motion system, with an angle accuracy of 0.04° and a repeatability accuracy of 0.04°. The swing angle of the second swing arm 5 is ±60°, which drives the detection mechanism to acquire the power curve of the fan-shaped trajectory.

[0029] Furthermore, it includes an openable and closable first housing for shielding ambient light during the measurement of the mold field diameter.

[0030] See Figure 2This embodiment also provides a hollow fiber mode field diameter measurement system, including the hollow fiber mode field diameter measurement unit and control unit described above; the control unit controls the detection mechanism to perform detection and construct a power distribution image of the measured end of the hollow fiber.

[0031] Specifically, the control unit is designed using an MCU+FPGA+DSP architecture, integrating electrical drive, image processing, and signal processing, and is based on a Linux operating system. The control unit also has an interface for interconnection with a computer, allowing the system to be controlled by a computer. Furthermore, this system can be connected to intelligent manufacturing systems (such as automatic measurement systems for the geometric parameters of hollow optical fibers) via standard network interfaces and protocols.

[0032] Furthermore, it includes a light source coupling unit; the light source coupling unit includes a tunable wavelength light source, a second and third-axis displacement stage, and a power detection module; the second and third-axis displacement stage fixes the light source input end of the hollow fiber, and the light source input end of the hollow fiber is coupled to the tunable wavelength light source; the power detection module detects the power of the light emitted from the hollow fiber, the control unit calculates the coupling efficiency based on the power of the light emitted from the hollow fiber and the output power of the tunable wavelength light source, and adjusts the second and third-axis displacement stage based on the coupling efficiency feedback to change the position of the light source input end of the hollow fiber until the coupling efficiency is greater than a set threshold.

[0033] Specifically, the three-axis displacement stage (including the first three-axis displacement stage 1 and the second three-axis displacement stage) has a stroke of ±2mm, a motion accuracy of 0.05um, and a motion speed of 5mm / s. The adjustable wavelength light source can be adjusted to O-band, C-band, or L-band, and the output power is greater than 80mw with a power fluctuation of less than 1%.

[0034] In this embodiment, the coupling efficiency threshold is set to 50%. When the coupling efficiency reaches the set threshold, the system will prompt that the measurement can start. After the measurement is manually started, the system will perform the measurement operation (in other embodiments of the present invention, the measurement can also be started automatically).

[0035] Furthermore, it includes an end-face detection unit; the end-face detection unit includes a background light compensation module and an end-face detection module; the background light compensation module is used to provide back illumination for the tested end of the hollow fiber, and the end-face detection module is used to acquire the end-face image of the tested end of the hollow fiber.

[0036] Specifically, before measuring the hollow fiber, the end face of the hollow fiber is cleaned with alcohol-soaked wiping paper. Then, a special instrument is used to cut the end face, and the prepared end face is inspected by the end face detection unit to ensure that the end face of the hollow fiber is clean and flat.

[0037] Furthermore, it is applicable to hollow optical fibers with a cladding diameter of 100um to 1mm.

[0038] Specifically, due to the use of a light source coupling unit, hollow optical fibers of different sizes can be adjusted to the ideal coupling position, which can adapt to the measurement of most commonly used hollow optical fibers.

[0039] Furthermore, the light source coupling unit includes an openable and closable second housing for shielding ambient light when calculating coupling efficiency.

[0040] The hollow fiber mode field diameter measurement system described in this invention has high stability and can accurately measure the mode field diameter parameters of hollow fibers (error < 0.2%, repeatability < 0.2%). The coupling quality of the hollow fiber under test and the sensitivity of the detector will affect the measurement results, so the system needs to be reset and calibrated before measurement. The system has a high degree of automation and is easy to operate. It only requires clamping both ends of the hollow fiber under test with hollow fiber clamps and placing it in the corresponding position of the test system.

[0041] The system has a dynamic range greater than 70 dB, a detector response greater than 0.9 A / W, and a detector response range of 1200 nm to 1700 nm.

[0042] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0043] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A hollow fiber mode field diameter measuring unit, characterized in that, It includes a displacement stage, a hollow rotation mechanism, a first swing arm, a rotary motor, a second swing arm, and a detection mechanism; The hollow rotating mechanism is fixed on the displacement stage, which is used to change the spatial position of the hollow rotating mechanism. The hollow rotating mechanism is a hollow ring structure with a ring rotating part on its outer side. One end of the first swing arm is connected to the ring rotating part, and the other end of the first swing arm is connected to the rotary motor. The rotating end of the rotary motor is connected to the second swing arm, and a detection mechanism is connected to the end of the second swing arm. During measurement, the end of the hollow fiber being measured is positioned at the center of the hollow rotating mechanism. The hollow rotating mechanism controls the first swing arm to move in a circular motion around the end of the hollow fiber, while the rotating motor controls the second swing arm to move in a circular motion around the rotating end. The detection mechanism forms a composite scanning trajectory under the combined drive of the hollow rotating mechanism and the rotating motor.

2. The hollow fiber mode field diameter measuring unit according to claim 1, characterized in that, The displacement stage is a first three-axis displacement stage, which is used to change the X, Y, and Z axis positions of the hollow rotating mechanism.

3. The hollow fiber mode field diameter measuring unit according to claim 1, characterized in that, The detection mechanism includes a patch cord bracket, an optical fiber patch cord, and a photoelectric converter. The patch cord bracket is connected to the end of the second swing arm. One end of the optical fiber patch cord is fixed to the patch cord bracket and serves as a scanning probe, while the other end is connected to the photoelectric converter. During measurement, the light emitted from the end of the hollow fiber being measured enters the optical fiber patch cord and is then transmitted to the photoelectric converter and converted into an electrical signal. The electrical signals obtained by the scanning probe at different positions characterize the power distribution characteristics of the end of the hollow fiber being measured.

4. The hollow fiber mode field diameter measuring unit according to claim 1, characterized in that, The measurement process includes: controlling the first swing arm to rotate at a preset step angle and then stopping through the hollow rotating mechanism; then controlling the second swing arm to swing at a preset angle through the rotary motor; repeating this process until the first swing arm has traversed the preset angle range of the hollow rotating mechanism.

5. The hollow fiber mode field diameter measuring unit according to claim 1, characterized in that, It includes an openable and closable first housing for shielding ambient light during the measurement of the mold field diameter.

6. A hollow fiber mode field diameter measurement system, characterized in that, It includes the hollow fiber mode field diameter measuring unit and control unit as described in any one of claims 1 to 5; the control unit performs detection by controlling the detection mechanism to construct a power distribution image of the measured end of the hollow fiber.

7. The hollow fiber mode field diameter measurement system according to claim 6, characterized in that, The system includes a light source coupling unit; the light source coupling unit includes a tunable wavelength light source, a second and third-axis displacement stage, and a power detection module; the second and third-axis displacement stage fixes the light source input end of the hollow fiber, and the light source input end of the hollow fiber is coupled to the tunable wavelength light source; the power detection module detects the power of the light emitted from the hollow fiber, the control unit calculates the coupling efficiency based on the power of the light emitted from the hollow fiber and the output power of the tunable wavelength light source, and adjusts the second and third-axis displacement stage based on the coupling efficiency feedback to change the position of the light source input end of the hollow fiber until the coupling efficiency is greater than a set threshold.

8. The hollow fiber mode field diameter measurement system according to claim 6, characterized in that, It includes an end-face detection unit; the end-face detection unit includes a background light compensation module and an end-face detection module; the background light compensation module is used to provide back illumination for the tested end of the hollow fiber, and the end-face detection module is used to acquire the end-face image of the tested end of the hollow fiber.

9. The hollow fiber mode field diameter measurement system according to claim 6, characterized in that, It is suitable for hollow optical fibers with cladding diameters of 100um to 1mm.

10. The hollow-core optical fiber mode field diameter measurement system according to claim 6, characterized in that, The light source coupling unit includes an openable and closable second housing, which is used to block ambient light when calculating coupling efficiency.

Images